The present invention relates to technology for recovering data at a certain point in time in the past in a computer system.
Data in a database (hereinafter, DB) utilized by a corporate computer system is generally stored in a storage device, and is managed by software called a database management system (hereinafter, DBMS). DB data (at least one piece of data of a plurality of data constituting a DB) is regularly backed up (in other words, a backup is implemented), and when a system failure occurs, the status at a desired point in time is recovered using backup data (DB data that has been backed up), and a log, which is a DB data update history.
A DB recovery process (a process for recovering DB data) that uses a log is nothing more than re-executing a data update as per an update history recorded in the log. For this reason, when the backup frequency is low, it is highly likely that recovery will have to be carried out from old DB data using a large quantity of logs, meaning that the time required for the DB recovery process will probably become quite long. Further, when the data integrity of the DB data (backup data and so forth), which forms the basis for a DB recovery process, has not been ensured, a DB recovery process must be carried out using even older logs in order to restore data integrity.
Technology aimed at shortening the time required for a DB recovery process, for example, is disclosed in literature 1 (Japanese Patent Laid-open No. 2004-252686). In literature 1, a storage device also acquires a data update history (hereinafter, storage journal). Consequently, data inside the storage device is returned to a state of an arbitrary point in time, thereby achieving an effect equivalent to frequently carrying out a backup. Further, information of a point in time when the integrity of the DB data inside the storage device is acquired from the DBMS, is simultaneously stored with this information inside the storage journal. This information is used to return the data inside the storage device to a point in time at which the DB recovery process will not take a lot of time.
Further, for reasons of enhancing computer system throughput, the configuration related to a computer system (hereinafter abbreviated as “system configuration”) is likely to change. Thus, there is the possibility that data backed up in the past will not be able to be used in the current system configuration. In Literature 2 (Japanese Patent Laid-open No. 2005-182588), there is disclosed technology, which holds configuration information from a computer at data backup time in a storage device, and ascertains if the backed up data is usable in the current system configuration.
For example, in the technology disclosed in literature 1, the system configuration is not taken into account. Thus, even if a storage journal is used to return to the state of the data inside the storage device at a certain point in time, there are instances when the computer cannot utilize this data due to the system configuration.
In the technology disclosed in literature 2, a determination is made as to whether or not backup data (data that has been backed up) is usable in the current system configuration. However, when it is determined that the backup data is not usable in the current system configuration, no support is given to change the system configuration. If backup data is not capable of being used in the current system configuration, construction (for example, restoration or new construction) of a system configuration that accords with the backup data will enable the backup data to be used. At present, the construction of this system configuration must be carried out manually by an administrator.